<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org"
      xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3">
<head>
<h2>Hello World!</h2>
</head>
<body>

<form action="login">
    登录名：<input type="text" name="username"/>
    <input type="submit" value="登录"/>
</form>
</body>
</html>